Electric clock system



25, 1932. s. BUEN 1,884 123 ELECTRIC CLOCK SYSTEM Filed Feb. 19. 1929 Mawr' batsmrizey Patented occ. 2s, 1932 UNITED STATES lPA'ri-:N'r ori-'ica SAUL IEILII, 0l' SPRINGFIELD, IABACHUBITTS, ABSIGNOB T0 Tn STANDARD ILEC TBIC '.lIEI COIPANY, NECTICU T OI'SPBINGFIED, IASSACHUSETT A GOBPOBATION 0l' CON- iinnc'rarc cLocx mm Application ma february is, im. semi no. 341,171.

This invention relates to electric clock systems in which impulses are transmitted from a master clock or other control apparatus to secondary clocks having electromagnets or other means for advancing the hands in response to the impulses, and particularly to systems in which the secondary hands are advanced in direct response to the impulses rather than indirectly through 'a rewinder which stores energy derived from the impulses for driving the hands continuously.

Objects of the invent-ion are to provide a system in which any one of the secondary clocks, if too fast or too slow, is corrected at predetermined intervals, as for example at the end of each hourly cycle, automatically and without interference with the normal operation of other secondary clocks in the system, which requires only a single circuit (two wires or one wire and ground) between the control apparatus and the secondary' clocks while permitting the use of a multiple circuit if desired, which is simple and economical in construction and reliable and dur rable in use, and which is generally superior to prior systems of this character.

In one aspect the invention is characterized by control apparatus for transmitting impulses of different characteristics (such as alternating current and direct current impulses) and at different time intervals (such as once per hour and once per minute respectively) together with secondary clocks normally driven by one kind of impulses and periodically synchronized by thel other kind of impulses. While slow secondaries may be advanced to synchronism in various ways, preferably a series of fast impulses are transmitted thereto during the period between the synchronizing or starting impulse and the next preceding normal or driving impulse, thereby to bring any of the secondaries which may be slow into position to be started in svnchronism with all the other secondaries when the starting impulse of high voltage or alternating` current or otherwise different) is transmitted.

The secondary clocks are characterized by an electromagnet or other means for advancing the hands in response to the driving impulses (minute impulses in the aforesaid -example) until the hands reach predetermined positions (with the minute hands in the minute positions, e. g.) together with means i for then rendering the aforesaid means ineffective further to advance the hands until a starting impulse is received. If a secondary be slow the aforesaid fast im ulses also function as driving impulses just fore the starting impulse initiates a new cycle or conditions the secondary clocks for a new cycle. The aforesaid means for rendering the secondary magnet ineffective may comprise means responsive only to alternating current for obstructing further advance of the secondary movementA by the secondary magnet, but it preferably comprises an impedance connected in circuit with the electromagnet so that the driving impulses do not energize the magnet suilcicntly to actuate the hands when the impedance is included in circuit. A. switch controlled by the secondary movement may be employed to short-circuit the impedance or otherwise conduct current to the magnet independently of the impedance at all times other than those when the magnet is intended to be responsive only to the startinimpulses.

or the purpose of illustrating the genus of the invention a typical concrete embodiment is shown in the accompanying drawing in which Fig. 1 is a diagram of one system;

Fig. 2 is an elevational view of the timer of the master clock;

Fig. 3 is an elevational clock movement; and

Fig. 4 is an elevation of a modified secondary movement.

The particular embodiment of the invention shown in Fig. 1 comprises a master clock having a circuit closer 1 which closes circuit at regular intervals such as once per minute, another circuit closer 2 which closes circuit at more frequent intervals such as once per second, acircuit controller 3 normally standing'in the neutral position shown in Fig. 1 and closing either circuit 4 or circuit 5 when moved toits lower or upper o- Sitions respectively, a timer 6 for controlling 'tacts 9 and 9 the circuit clor 3 and turning at a constant s referabl one revolution per hour, an eleetibiiiagnet 7y for controlling switches 8 and 8 the'switches normally engaging con- -and being lifted into engagement with the contacts 10 and 10 whenv the magnet 7 is energlzed, an electromagnet 11 controlled by the switches 1 and 2 for closing the switch 12 when energized, and a transformer having a primary 13 connected to a source of alternating current and a secondary 14 connected to a rectifier 15 through swltch 12, the line L leading to the secondary clocks S and S being connected across the secondary 14 when the switches 8 and 8' are in upper osition and being connected across the recti er 15 when the switches 8 and 8 are in the lower position.

The periphery of the timer 6 engages the switch arm 3 through a lug 16 which is held against the timer by spring 17. The periphery is provided with a cam projection 18 which depresses the switch arm 3 into contact with the terminal of circuit 4 for a brief interval during each revolution of the timer, as for example from fifty-nine minutes and ten seconds to fifty-nine minutes and forty seconds. Immediately following the projection 18 is a depression 19 into which the lug 16 is moved by spring 17 as soon as the projection passes, preferably just before the master clock reaches the sixty-minute position, thereby to close circuit 5 while the minute circuit closer 1 sends the sixtieth ininute impulse. The timer 6 ma also be provided with any number of epressions 2O and 21 to permit the circuit closer 3 to close the circuit 5, through electromagnet 7 and source 22, at intervals intermediate the sixtyminute positions, for example while the circuit closer 1 sends the nineteenth and thirtyninth minute impulses.

The an ular positions of the projection 18 and the epressions 19, 2O and 21 are indicated in Fig. 2 where the numerals at the ends of the radial lines indicate the times when the respective points of the circumference of the timer intersected by the radial lines pass the lug 16 on arm 3.

The secondary clock movement diagrammatically illustrated in Fig. 3 comprises an electromagnet D for driving the ratchet wheel 23 through a pawl 24 on arm 25 pivoted at 26. Arm 25 carries a stop 27 for engagement with a secondratchet wheel 28 fast to shaft 29 upon which the ratchet wheel 23 is fastened to prevent overthrow by pawl 24, a pawl 29 pivoted at 30 and engaging with ratchet wheel 23 preventing retrograde movement of the ratchet wheels. Fast to shaft 29 1s an arm 30 for engagement with a projection on a switch spring 31 normally engaging contact 32 and moved by arm 30 out of engagement with contact 31 when the secondary clock reaches a predetermined position (e. g.

`the condenser 37 is included in the circuit.

The operation of the system illustrated in Figs. 1, 2 and 3 is as follows: With the swztch 3 normally standin in neutral position at the master clock t e minute circuit closer 1 energizes electromagnet 11 once per minute, thereby closing switch 12 at minute intervals to send minute impulses to the secondary clocks, the switch 8 standing in the lowermost position so that these impulses are of rectified current. With switch 31 at the secondary clock in upper position these impulses are transmitted to the electromagnet D to advance the secondary hands through a one-minute interval at each impulse. Between the fifty-nine and sixtyminute positions of the master clock the switch 3 is depressed to connect the seconds impulse circult-closer 2 in circuit with the electromagnet 11, thereby to send impulses once per second to the secondary clock during a part of this minute, for example from fiftyute positions when the master clock reaches its fifty-nine minute position (and likewise at every other minute position) so that the secondary clocks, if running normally, are never behind the master clock; although it will of course be understood that the secondaries might be adjusted to advance to each new position only when the master clock has reached that position.

When the secondary clocks have reached the sixty-minute position, the impedance 37 at each secondary is included in circuit as illustrated at the lower right corner of Fig. 1, this impedance being adapted to render the rectified impulses ineffective to actuate the electromagnet D. In the case of those secondary clocks which are on time the impedance 37 will be included in circuit on the fty-ninth impulse of the minute circuit closer 1. In the case of those secondary clocks which are too fast the impedance 37 will be included in circuit before the master clock has depressed the switch 3, so that all succeeding impulses by either the minute switch 1 or the seconds impulse switch 2- will be ineffective to actuate the electromagnets D until the sixty-minute impulse is transmitted.

mamas I Those seconda clocks which are too slow will be advan to the sixty-minute position by tlheelseconds impulse switch 2 as above descri With the hands of all of the secondary clocks/in the sixty-minute position, when the timer 6 reaches the sixty-minute position the lug 16 on the switch 3 moves into therecess 19, thereby closing the circuit of electromagnet 7 to lift switches 8 and 8 into engagement with contacts 10 and 10 whereupon the secondary 14 is connected directly to line L. Thus when the minute hand 1 energizes the electromagnet 11 to close switch 12 at the end of the sixtieth minute, an impulse of alternating current is transmitted to the secondar clocks, the electromagnets D of which are a justed to respond to these alternating current impulses through the impedance 37. Thus the hands of the secondary clocks are started on a new hourly cycle by this alternating current impulse, and after the hands have moved to the one-minute position the switches 31 are permitted to spring upwardly into engagement with contacts 32, thereby rendering the electromagnets D responsive to the normal impulses of direct current. After the alternating current impulse is transmitted by the master clock the lug 16 rides out of the recess 19, thereby restoring the switch 3 to neutral position and permitting the switches 8 and 8' to move back against contacts 9 and 9. The normal direct current impulses may then be transmitted continually for fifty-nine minutes; or, as illustrated in Figs. 1 and 2, alternating current impulses may be transmitted at the nineteen and thirty-nine minute positions of the master clock by providing the additional recesses 20 and 21, so that any secondary clock which failed to respond to the sixty-minute impulse of alternating current (or which failed to receive the impulse due to current interruption or other cause) need not wait a full hour for another starting impulse. Normally the secondary clocks will of course respond to the nineteenth and thirtyninth minute impulses of alternating current as they do to the low voltage impulses.

Instead of providing the secondary clocks with a single magnet D and switch 31-32 they may be provided with two magnets D and S as shown in Figs. 1 and 4, the magnet D functioning in the same way as magnet D and the magnet S serving to stop the clock movement in the sixty-minute position by providing' its armature with a stop 46 in the path of arm 47 fast to the shaft 29. By connecting the two magnets S and D in parallel as shown in Fig. 1 and providing a condenser 37 in the branch of magnet S so that this magnet will respond only to alternating current impulses, the clock movements will remain in the sixty-minute position until alternating current impulse causes electromagnets S to move the stops 46 out of thepaths' of the 'arms 47, the same alternating current impulse which energized' magnets also energizing magnets D to advance the clock movements one ste so that the arms 47 will pass the stops 46 fore the latter drop back.

From the foregoing it will be evident that this invention affords a remarkably simple and reliable clock system. For example the secondary clocks may be fully controlled with a. single-circuit magnet (or magnets as disclosed in my copending application filed on even date herewith) in contra-distinction to magnets havin a plurali-ty of windings and requiring mu tiple circuits such as differentially wound magnets heretofore used. Moreover, the secondaries may be synchronized by a momentary starting impulse, preferably lasting only a small .fraction of a minute, whereas prior systems have required the application of current for as long as fifteen minutes. v

While the impulse of high voltage of different kind is herein referred to as a starting impulse inasmuch as it initiates a new cycle, it may of course be regarded as the last impulse of each cycle, especially when the secondary clocks are adjusted to move from their ifty-nine-minute positions to their sixty-minute positions in response to the sixty-minute impulse instead of the tlftynine-minute impulse'of the master clock.

I claim:

1. An electric clock system of the type having a control station for sending alternating current and direct current impulses and secondary clocks having electromagnetic means responsive to one kind of impulses for advancing the hands to predetermined positions and other magnetic means responsive only to the other kind of impulses for further advancing the hands, vcharacterized by a single circuit for transmitting both classes of impulses from the control station to the secondary clocks.

2. An electric clock system comprising a control station interconnected with secondary clocks through a single circuit, means at the control statlon for transmitting alternating current impulses and direct current impulses over said circuit, electroma etic means at the secondary clocks responslve to the direct current impulses received over said circuit for advancing the hands to redetermined positions, means at the secon ary clocks for restricting further advance of the hands until an alternating current impulse is received over the same single circuit, and other electromagnetic means responsive to alternating currents for effecting further advance of the hands.

3. A secondary clock system of the impulse type comprising a clock train, means including an electromagnetic winding for moving the clock train in recurrent cycles in response l to impulses, means for terminating further advance of the clock train at a predetermined point in each cycle if the clock is fast, means including a second electromagnetic winding in the secondary clock controlling further advance ofthe clock train, said last means being unresponsive to said impulses 'and one of said first and last means being reponsive only to alternating current.

Signed by me at Boston, Massachusetts, this 15th day of February, 1929.

SAUL KEILIEN. 

